Implementation of the Smbus interface using the Linux kernel's user-space support. More...

#include <DevSmbus.hpp>

Inheritance diagram for duds::hardware::interface::linux::DevSmbus:

Collaboration diagram for duds::hardware::interface::linux::DevSmbus:

Public Member Functions
	DevSmbus (const std::string &devname, int devaddr, bool pec=true)
	Opens the device file for the bus. More...

	DevSmbus (const std::string &devname, int devaddr, UsePec)
	Opens the device file for the bus and specifies that Packet Error Checking (PEC) will be used. More...

	DevSmbus (const std::string &devname, int devaddr, NoPec)
	Opens the device file for the bus and specifies that Packet Error Checking (PEC) will not be used. More...

	~DevSmbus ()
	Closes the device file. More...

virtual int	address () const
	Returns the address of the device that this object will attempt to communicate with. More...

virtual std::uint16_t	call (std::uint8_t cmd, std::uint16_t word)
	Does a process call operation. More...

virtual void	call (std::uint8_t cmd, const std::vector< std::uint8_t > &out, std::vector< std::uint8_t > &in)
	Does a block process call operation. More...

virtual int	receive (std::uint8_t cmd, std::uint8_t *in, const int maxlen)
	Sends a command byte, then reads a block of data from the device. More...

virtual void	receive (std::uint8_t cmd, std::vector< std::uint8_t > &in)
	Sends a command byte, then reads a block of data from the device. More...

virtual std::uint8_t	receiveByte ()
	Read a single byte from the device without sending a command/register byte first. More...

virtual std::uint8_t	receiveByte (std::uint8_t cmd)
	Sends a command byte, then reads a single byte from the device. More...

virtual std::uint16_t	receiveWord (std::uint8_t cmd)
	Sends a command byte, then reads a word, two bytes, from the device. More...

virtual void	transmit (std::uint8_t cmd, const std::uint8_t *out, const int len)
	Sends a command byte and a block of data to the device. More...

virtual void	transmitBool (bool out)
	Sends a single bit to the device. More...

virtual void	transmitByte (std::uint8_t byte)
	Sends a single byte to the device. More...

virtual void	transmitByte (std::uint8_t cmd, std::uint8_t byte)
	Sends a command byte and a data byte to the device. More...

virtual void	transmitWord (std::uint8_t cmd, std::uint16_t word)
	Sends a command byte and a data word to the device. More...

Public Member Functions inherited from duds::hardware::interface::Smbus
virtual	~Smbus ()=0

std::uint16_t	receiveWordBe (std::uint8_t cmd)
	Sends a command byte, then reads a big-endian word from the device. More...

void	transmit (std::uint8_t cmd, const std::vector< std::uint8_t > &out)
	Sends a command byte and a block of data to the device. More...

void	transmitWordBe (std::uint8_t cmd, std::uint16_t word)
	Sends a command byte and a big-endian data word to the device. More...

Private Member Functions
void	io (i2c_smbus_ioctl_data &sdat)
	Sends I/O requests to the kernel, then checks for an error and if found throws the appropriate exception. More...

Private Attributes
int	addr
	The device (slave) address; used for error reporting. More...

std::string	dev
	Stores the device file name for later error reporting. More...

int	fd
	The file descriptor for the open device. More...

Detailed Description

Implementation of the Smbus interface using the Linux kernel's user-space support.

This requires that the kernel be built with support for the SMBus or I2C master, and support for user-space I2C access. If the support is in kernel modules, they must be loaded along with the i2c-dev module. Using the kernel's i2c-gpio driver should be more efficient than implementing the SMBus protocol with user-space GPIO support.

All thrown exceptions will include an attribute of boost::errinfo_file_name with the device file name, along with SmbusDeviceAddr.

The name follows SysFsGpio in naming the kernel interface, and it avoids using the same name as the base class which I figured might lessen confusion.

Author: Jeff Jackowski

Examples:: apds9301test.cpp, and ina219test.cpp.

Definition at line 40 of file DevSmbus.hpp.

Constructor & Destructor Documentation

◆ DevSmbus() [1/3]

duds::hardware::interface::linux::DevSmbus::DevSmbus	(	const std::string &	devname,
		int	devaddr,
		bool	pec = `true`
	)

Opens the device file for the bus.

Parameters

devname	The path to the device file, usually /dev/i2c-N where N is the number assigned to the bus.
devaddr	The device, or slave, address used as the destination of communications.
pec	True (default) to enable use of Packet Error Checking. If the device supports PEC, this should be used to help prevent bad data over the bus from causing trouble.

Exceptions

SmbusErrorUnsupported	Either PEC requested but not supported, or a 10-bit address was requested but is not supported by the kernel's driver.
SmbusErrorNoBus	The device file could not be opened or failed to accept the device address.

Definition at line 24 of file DevSmbus.cpp.

◆ DevSmbus() [2/3]

duds::hardware::interface::linux::DevSmbus::DevSmbus	(	const std::string &	devname,
		int	devaddr,
		UsePec
	)

inline

Opens the device file for the bus and specifies that Packet Error Checking (PEC) will be used.

Parameters

devname	The path to the device file, usually /dev/i2c-N where N is the number assigned to the bus.
devaddr	The device, or slave, address used as the destination of communications.

Exceptions

SmbusErrorUnsupported	Either PEC requested but not supported, or a 10-bit address was requested but is not supported by the kernel's driver.
SmbusError	The device file could not be opened or failed to accept the device address.

Definition at line 88 of file DevSmbus.hpp.

◆ DevSmbus() [3/3]

duds::hardware::interface::linux::DevSmbus::DevSmbus	(	const std::string &	devname,
		int	devaddr,
		NoPec
	)

inline

Opens the device file for the bus and specifies that Packet Error Checking (PEC) will not be used.

Parameters

devname	The path to the device file, usually /dev/i2c-N where N is the number assigned to the bus.
devaddr	The device, or slave, address used as the destination of communications.

Exceptions

SmbusErrorUnsupported	A 10-bit address was requested but is not supported by the kernel's driver.
SmbusError	The device file could not be opened or failed to accept the device address.

Definition at line 102 of file DevSmbus.hpp.

◆ ~DevSmbus()

duds::hardware::interface::linux::DevSmbus::~DevSmbus ( )

Closes the device file.

Definition at line 53 of file DevSmbus.cpp.

Referenced by DevSmbus().

Member Function Documentation

◆ address()

int duds::hardware::interface::linux::DevSmbus::address ( ) const

virtual

Returns the address of the device that this object will attempt to communicate with.

Implements duds::hardware::interface::Smbus.

Definition at line 285 of file DevSmbus.cpp.

Referenced by DevSmbus().

◆ call() [1/2]

std::uint16_t duds::hardware::interface::linux::DevSmbus::call	(	std::uint8_t	cmd,
		std::uint16_t	word
	)

virtual

Does a process call operation.

Sends a command byte and a word to the device, then receives a word.

Parameters

cmd	The command or register byte.
word	The word to send.

Returns: The word received from the device.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 248 of file DevSmbus.cpp.

Referenced by DevSmbus().

◆ call() [2/2]

void duds::hardware::interface::linux::DevSmbus::call	(	std::uint8_t	cmd,
		const std::vector< std::uint8_t > &	out,
		std::vector< std::uint8_t > &	in
	)

virtual

Does a block process call operation.

Sends a command byte and block of data to the device, then receives a block of data.

Parameters

cmd	The command or register byte.
out	The data block to send. It must not have more than 32 bytes.
in	The data block received from the device.

Exceptions

SmbusErrorMessageLength	A request was made to send a block of more than 32 bytes.
SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 261 of file DevSmbus.cpp.

◆ io()

void duds::hardware::interface::linux::DevSmbus::io ( i2c_smbus_ioctl_data & sdat )

private

Sends I/O requests to the kernel, then checks for an error and if found throws the appropriate exception.

Definition at line 57 of file DevSmbus.cpp.

Referenced by call(), receive(), receiveByte(), receiveWord(), transmit(), transmitBool(), transmitByte(), and transmitWord().

◆ receive() [1/2]

int duds::hardware::interface::linux::DevSmbus::receive	(	std::uint8_t	cmd,
		std::uint8_t *	in,
		const int	maxlen
	)

virtual

Sends a command byte, then reads a block of data from the device.

Parameters

cmd	The command or register byte.
in	The input buffer.
maxlen	The maximum amount of data to write into in.

Returns: The number of bytes received from the device.

Exceptions

SmbusErrorMessageLength	The buffer in could not hold all the received data.
SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 194 of file DevSmbus.cpp.

Referenced by DevSmbus().

◆ receive() [2/2]

void duds::hardware::interface::linux::DevSmbus::receive	(	std::uint8_t	cmd,
		std::vector< std::uint8_t > &	in
	)

virtual

Sends a command byte, then reads a block of data from the device.

Parameters

cmd	The command or register byte.
in	The input vector. Upon success, the vector will be resized to match the received data.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 213 of file DevSmbus.cpp.

◆ receiveByte() [1/2]

std::uint8_t duds::hardware::interface::linux::DevSmbus::receiveByte ( )

virtual

Read a single byte from the device without sending a command/register byte first.

Returns: The byte from the device.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 122 of file DevSmbus.cpp.

Referenced by DevSmbus().

◆ receiveByte() [2/2]

std::uint8_t duds::hardware::interface::linux::DevSmbus::receiveByte ( std::uint8_t cmd )

virtual

Sends a command byte, then reads a single byte from the device.

Parameters

cmd	The command or register byte.

Returns: The byte from the device.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 146 of file DevSmbus.cpp.

◆ receiveWord()

std::uint16_t duds::hardware::interface::linux::DevSmbus::receiveWord ( std::uint8_t cmd )

virtual

Sends a command byte, then reads a word, two bytes, from the device.

Parameters

cmd	The command or register byte.

Returns: The word from the device.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 170 of file DevSmbus.cpp.

Referenced by DevSmbus().

◆ transmit()

void duds::hardware::interface::linux::DevSmbus::transmit	(	std::uint8_t	cmd,
		const std::uint8_t *	out,
		const int	len
	)

virtual

Sends a command byte and a block of data to the device.

Parameters

cmd	The command or register byte.
out	The data to send.
len	The number of bytes in the buffer out to send. It must be between 1 and 32, inclusive.

Exceptions

SmbusErrorMessageLength	A request was made to send a block of less than 1 or more than 32 bytes.
SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 226 of file DevSmbus.cpp.

Referenced by DevSmbus().

◆ transmitBool()

void duds::hardware::interface::linux::DevSmbus::transmitBool ( bool out )

virtual

Sends a single bit to the device.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 112 of file DevSmbus.cpp.

Referenced by DevSmbus().

◆ transmitByte() [1/2]

void duds::hardware::interface::linux::DevSmbus::transmitByte ( std::uint8_t byte )

virtual

Sends a single byte to the device.

Parameters

byte	The byte to send.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 134 of file DevSmbus.cpp.

Referenced by DevSmbus().

◆ transmitByte() [2/2]

void duds::hardware::interface::linux::DevSmbus::transmitByte	(	std::uint8_t	cmd,
		std::uint8_t	byte
	)

virtual

Sends a command byte and a data byte to the device.

Parameters

cmd	The command or register byte.
byte	The data byte to send.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 158 of file DevSmbus.cpp.

◆ transmitWord()

void duds::hardware::interface::linux::DevSmbus::transmitWord	(	std::uint8_t	cmd,
		std::uint16_t	word
	)

virtual

Sends a command byte and a data word to the device.

Parameters

cmd	The command or register byte.
word	The data word to send.

Exceptions

SmbusErrorPec	The PEC checksum was not valid for the data.
SmbusErrorBusy	The bus was in use for an inordinate length of time. This is not caused by scheduling on the same host computer.
SmbusErrorNoDevice	The device did not respond to its address.
SmbusErrorUnsupported	This operation is unsupported by the master.
SmbusErrorProtocol	Data from the device does not conform to the SMBus protocol.
SmbusErrorTimeout	The operation took too long resulting in a bus timeout.
SmbusError	A general error that doesn't fit one of the other exceptions.

Implements duds::hardware::interface::Smbus.

Definition at line 182 of file DevSmbus.cpp.

Referenced by DevSmbus().

Member Data Documentation

◆ addr

int duds::hardware::interface::linux::DevSmbus::addr

private

The device (slave) address; used for error reporting.

Definition at line 52 of file DevSmbus.hpp.

Referenced by address(), call(), DevSmbus(), io(), receive(), and transmit().

◆ dev

std::string duds::hardware::interface::linux::DevSmbus::dev

private

Stores the device file name for later error reporting.

Definition at line 44 of file DevSmbus.hpp.

Referenced by call(), DevSmbus(), io(), receive(), and transmit().

◆ fd

int duds::hardware::interface::linux::DevSmbus::fd

private

The file descriptor for the open device.

Definition at line 48 of file DevSmbus.hpp.

Referenced by DevSmbus(), io(), and ~DevSmbus().

The documentation for this class was generated from the following files:

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ DevSmbus() [1/3]

◆ DevSmbus() [2/3]

◆ DevSmbus() [3/3]

◆ ~DevSmbus()

Member Function Documentation

◆ address()

◆ call() [1/2]

◆ call() [2/2]

◆ io()

◆ receive() [1/2]

◆ receive() [2/2]

◆ receiveByte() [1/2]

◆ receiveByte() [2/2]

◆ receiveWord()

◆ transmit()

◆ transmitBool()

◆ transmitByte() [1/2]

◆ transmitByte() [2/2]

◆ transmitWord()

Member Data Documentation

◆ addr

◆ dev

◆ fd